TAD measured from the interventricular septum (TADs). The upper image was the apical 4-chamber view, the lower curve was the M-mode line of the interventricular septum. TADs was the distance measured from the highest to the lowest of the line (in the above image).
Li et al. Scoliosis 2013 8:1 doi:10.1186/1748-7161-8-1